The connection between TTF-1 and ABCA1. ABCA1 has been shown to be negatively regulated through miRNAs including miR-33a, miR-200-3p, and miR-106a. Lai et al. suggested that TTF-1, miR-33a, and ABCA1 may form an incoherent feed-forward loop (TTF-1 → ABCA1; TTF-1 → miR-33a—|ABCA1) [22]. Treatment with Valproic Acid (VPA) enhanced cisplatin sensitivity of non-small-cell lung cancer (NSCLC) cells via HDAC2 mediated down-regulation of ABCA1. Efatutazone treatment increased mRNA and protein expression of PPAR-gamma, LxR-alpha and ABCA1, suggesting that Efatutazone functions through PPAR-gamma/LxR-alpha/ABCA1 pathway. cAMP also can regulate ABCA1 expression. The fact that TTF-1 is a lung lineage master regulator highlights the fact that cholesterol efflux factors may be regulated in a tissue-specific manner.